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B. ECK

April 2, 1963 FANS 4 Sheets-Sheet 1 Original Filed March 1, 1955 IN V ENTOR. 20 fl/W M haw: 5 1M April 2, 1963 B. ECK Re. 25,365

FANS

Original Filed March 1, 1955 4 Sheets-Shed. 2

April 2, 1963 B: ECK Re. 25,

FANS

Original Filed March 1, 1955 4 Sheets-Sheet 5 I' Ill l-jl INVENTOR. flm4% BY ha /6 f- JAn fie/ April 2, 1963 B. ECK Re. 25,365

Original Filed March 1, 1955 4 Sheets-Sheet 4 United States Patent25,365 FANS Bruno Ech, Kolndilettcnberg, Germany Original No. 2,942,773,dated June 28, 196i), Ser. No. 493,432, 1, 1955. Appiication for rei sueJune 29, 196i, Ser. No. 120,791. In Germany .liuly 17, 1953 Public Law61%, Aug. 23, 195-2- Pateut expires July 127, 1973 17 (Ilaims. (Ci.Kati-125) Matter enclosed in heavy brackets :8 appears in the originalpatent but forrns no part of this reissue specification; matter printedin italics indicates the additions made by reissue.

The present invention relates to fans.

In general there are two classical types of well known fans, namely, theaxial flow type of fan and the radial flow type of fan. Both of theseknown types of fans have disadvantages. Thus, (these known fansinvariably make agreat amount of noise during their operation andconsiderable problems are involved in locating such fans in smallspaces. Furthermore, it is difficult without replacing one of theseknown fans to provide great variations in the output.

One of the objects of the present invention is to overcome the abovedrawbacks by providing a fan which will operate with far less noise thanthe above-discussed conventional fans, will provide a higher Output thanthe known fans for a given size and speed of rotation of the fans, andwill be capable of providing a wide range in output simply by changingthe speed of rotation of the fan.

Another object of the present invention is to provide a fan which,except for the motor which drives the same, may be entirely locatedwithin a duct so that a minimum of space is required ior the fan of theinvention.

A further object of the present invention is to provide an arrangementaccording to which almost any desired number of fans may be connected tothe same source of energy to be driven thereby.

An additional object of the vide a fan construction which to any givenconditions.

Also, the objects of the present invention includes the provision of afan which may be constructed of well known materials and with the sametools as are used for the construction of conventional fans.

With the above objects in view the present invention mainly consists ofa fan which includes a plurality of elongated impellcr blades or"substantially the same length uniformly distributed about a cylindricalspace and respectively having inner side edges located along a firstcylinder and outer side edges located along a second cylinder coaxialwith and greater than the first cylinder, these blades beingsubstantially parallel to the common axis of the cylinders. A casingmeans supports the impeller means for rotation about this common axis,and this casing means is formed with an inlet communicating at any giveninstant with a first plurality of blades located on one side of theabove-mentioned axis and with an outlet communicating at any giveninstant with a second plurality of blades located at an opposite side ofthis axis, the casing means also including a first arcuate wall portionextending from the inlet to the outlet and located closely adjacent toand conforming to the curvature of the above-mentioned second cylinderand a second arcuate wall portion opposite this first wall portion, alsoextending from the inlet to the outlet of the casing means, and havingend portions respectively located adjacent the inlet and outlet with theend portion adjacent the inlet located nearer to the abovementioned axisthan the end portion adjacent the outlet, so that this second wallportion of the casing forms with the above-mentioned second cylinder agap which conpresent invention is to promay be very easily adapted Pie.253%.; Reissueel Apr. 2, I963 2 verges along a portion of its lengthfrom said Einlet] outlet toward said {outlet} inlet.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantage thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings, inwhich:

FIG. 1 is a sectional side elevational view of a fan constructed inaccordance with the present invention;

FIG. 2 is a fragmentary view corresponding to FIG. 1 of part of the fanof FIG. 1 with a difierent structure located within the fan;

FIG. 3 is a fragmentary sectional view taken along the line 3-3 of FIG.1 in the direction of the arrows;

FIG. 4 is a side sectional view taken along the line 44 of FIG. 5 in thedirection of the arrows of another fan constructed in accordance withthe present invention, FIG. 4 showing the dimensional relationshipsbetween the parts of the fan of the present invention;

FIG. 5 is a plan view of the fan of FIG. 4;

FIG. 6 is a sectional view taken along the line 66 of FIG. 5 in thedirection of the arrows;

FIG. 7 is a schematic side view of another form of fan constructed inaccordance with the present invention;

FIG. 8 is an end view of the fan of FIG. 7 as seen from the left side ofFIG. 7;

FIG. 9 is a top plan View of the fan of FIG. 7;

FIG. 10 is a schematic side view of still another form of fanconstructed in accordance with the present invention;

FIG. 11 is a schematic side elevational View of a further form of a fanconstructed in accordance with the present invention; and

FIG. 12 shows in a schematic side elevational view a still furtherembodiment of the present invention.

Before proceeding to a detailed discussion of the drawings shown in thisapplication, it is pointed out that the fan of the present inventiondiffers basically from. known fans in that it cannot be classifiedeither as a radial flow fan or as an axial flow fan. According to thepresent invention air is sucked into the fan of the invention throughthe spaces between some oi the impeller blades of the fan and this air(or other fluid) passes across the interior of the 'fan and moves outthrough the spaces between some of the impeller blades, at a particularinstant. Thus, with the fan of the present invention the fluid flowstwice through the blades of the impeller.

Referring now to the drawings, FIG. 1 shows an impeller 1 provided withimpeller blades distributed along a cylinder, as is evident from FIG. 1,the impeller l turning in a clockwise direction, as viewed in FIG. I,and as indicated by the arrow of FIG. 1. The impeller blades of theimpeller 1 are located about a cylindrical space 2 within which guides 3and 4 for the air are located. The impeller is supported for rotation bya casing which is formed with an inlet 5 and an outlet 6, and it will benoted that the inlet angle extending from point 7 to point 3 indicatedin FIG. 1 is greater than the outlet angle extending from point 9 topoint ill indicated in FIG. 1. FIG. 3 shows the manner in which theimpeller and guides 3 and 4 are mounted on the casing 15. Thus, thiscasing 15 includes side walls 16 and 17, and the guides 3 and 4, as wellas the several guides shown in FIG. 1 between the guides 3 and 4, extendbetween and are fixed to a pair of end plates 13 and 19. The end plate18 is fixed to a pair of studs 26 which extend to and are fixed to theside wall 17, and the end plate 19 is located Within the impeller 1.This impeller l is coaxial with the cylinder in which the guides arelocated, and the blades of the impeller are carried by a pair of rings21 and 22 which are slidable on the peripheries of the end plates 19 and18, respectively, so that these end plates form bearings for theimpeller. The ring 21 is in the form of an annular flange integral witha plate 23 fixed to a shaft 24 which extends through side wall 16 of thecasing 15 and which is turna-bly supported by the side wall, a pulley 25or the like being fixed to the shaft 24 so that in this way impeller 1may be driven.

In operation, as the impeller 1 turns in a clockwise direction, asviewed in FIG. 1, the blades of the impeller suck air in through theinlet 5, force this air along the space 2 where the guides for the airare located, and the air is forced again through the impeller blades outthrough the outlet 6. It will be noted that the angle of the inlet aboutthe axis of rotation of the impeller is greater than that of the oulet6.

FIG. 2 shows a fan identical with that of FIG. 1 except that theinterior of the space surrounded by the impeller is provided, inaddition to the guide 3, with a single guide and a plurality ofstationary vanes 11, as indicated in FIG. 2, the guides of FIG. 2operating in the same way as the guides of FIG. 1 to direct the airacross the space surrounded by the impeller.

FIGS. 46 show a preferred construction of a fan in accordance with thepresent invention. Thus, referring to FIGS. 4-6 it will be seen that thefan disclosed therein includes a casing 30 in which the impeller 31 issupported for rotation. As may be seen from FIG. 6, the impeller 31 iscarried for rotation by the side walls 32 of the casing 30. The impellerincludes a pair of circular, coaxial, endplates 33 each of which isfixed to a shaft 34 extending outwardly through an opening in a sidewall 32 to be turnably supported by the casing 30. The right shaft 34 ofFIG. 6 is fixed to a pulley 35 so that with abelt a drive may betransmitted from any suitable motor or the like to the impeller. Theblades 36 are located between and fixed to the end plates 33, and itwill be noted that with the fan of FIGS. 46 there is absolutely nothingin the space surrounded by the impeller. Itwillbe noted from FIGS. 5 and6 that the impeller is quite long, and in fact it is possible to makethe impeller blades of any desired length without in any way alteringthe operation of the fan of the invention.

As may be seen from FIG. 4, the casing 30 is provided with an inlet 37which converges as it approaches the impeller 31 and with an outlet 38which diverges as it leaves the impeller 31. Furthermore, it will .benoted that, as was the case with the embodiment of FIG. 1, the anglethrough which the inlet 37 extends about the axis 39 of the impeller islarger than the angle through which the outlet 38 extends about thisaxis. The inlet and outlet ducts each communicates with the rotor at theperiphery thereof over an angle of at least 90, as is evident from FIG.4.

It has been found empirically that in order to produce the best possibleresults it is necessary for the elements of the fan of the inventioin tohave certain relationships with respect to each other, and suchrelationships are indicated in FIG. 4. FIG. 4 shows a fan where theoutlet 38 extends in general along a direction, taken at random,parallel to the plane 40 passing through the axis of the in1- peller,and the inlet 37 extends in a direction parallel to the horizontal plane41 shown in FIG. 4. In order to show the relationship between theseveral elements of the fan of the invention, it is assumed that thecylinder along which the inner side edges of the blades 42 of theimpeller are located has a radius of 1. With such a radius of 1 for thisinner cylinder, the outer cylinder along which the outer side edges ofthe blade 42 are located, will have a radius of approximately 1.25.Furthermore, each of the blades 42 itself forms-part of a cylinder. Itis preferred to provide 36 blades on the impeller so that the blades arespaced from each other by 10, and the cylinder of which each blade formsa part has a radius 43 which is approximately as long as the distancebetween each pair of adjacent blades, the ccnter of radius 43 beinglocated between the inner and outer cylinders 44 and 45 in which theinner side edges and outer side edges of the blade 42 are respectivelylocated. The center of the radius 43 may be located midway betweencylinders 44 and 45 at a distance of 1.125 from the axis 39.

The inner edge of each blade 42 is curved in the direction of rotationof the impeller.

On the other hand, the outer side edge of each blade 42 may make anangle of between 25 and 40 with a tangent to the cylinder 45, as shownin FIG. 4. Thus, it has been found by test that the particular anglemade by the outer side edge of each blade with the outer cylinder 45 isnot particularly critical as long as it is somewhere between 25 :and40". Thus, actual fans constructed in accordance with the presentinvention and operating very successfully have had angles at the outerside edges of the blades, respectively with the cylinder 45 of 26 andalso of 38. However, the angle of the inner side edge of each blade witha tangent to the cylinder 44 is always 70 or very close thereto.

The casing 30 includes a wall portion 46 extending from the inlet to theoutlet and an opposite wall portion 48 extending from the inlet to theoutlet. As is evident from FIG. 4, the wall portion 46 is locatedclosely adjacent to and corresponds closely to the curvature of thecylinder 45. It has been found best to terminate the wall portion 46 atits inlet end at a distance of 0.9 from the plane 40, as indicated inFIG. 4, and the wall portion 46 merges beyond this point with the partof the casing 30 which forms the inlet 37. The opposite end of the wallportion 46 preferably formed along a curve having a radius ofapproximately 2.4, the center of this radius being located at a distanceof approximately 0.9 from plane 47 which is normal to the plane 40 andat a distance of 0.5 from the plane 40, as shown in FIG. 4. Furthermore,it will be noted that the top wall of the outlet 38, as viewed in FIG.4, is located in a plane which is perpendicular to the axis 47.

A particular feature of the invention resides in the configuration ofthe wall 48 of the casing 30. This wall 48 has a radius of curvatureslightly less than 1, such as, for example, 0.9. Furthermore, thisradius has its center spaced by 0.2 from plane 40 and 0.6 from plane 47,as shown in FIG. 4. It will be noted that wall portion 48 thus has itsend portion next to the inlet 37 located nearer to the axis 39 than itsend portion next to the outlet 38, and as a result the wall portion 48forms with a cylinder 45 a gap which converges as it approaches theinlet 37. At the point where the wall portion 48 is locatedfurthestfromthe axis 39 it extends toward the outlet 38 along a tangentto this point so that this tangential part of wall portion 48 makes anangle of with the radius of curvatom of Wall portion 48 at this pointfurthest from the axle 39.

As a result of this latter feature of the invention, the impeller 31when driven in a clockwise direction, as viewed in FIG. 4, creates awhirling body of air 49-ind icated'in dot-dash lines in FIG. 4. Thiswhirling body of air acts in the same way as a solid guide of the typeshown in FIGS. 1 and 2 so that it is possible toeliminate-suchsolidguides With the construction shown in FIG. 4. The whirling body ofair 49 which moves continuously in-a clockwise direction, as theimpeller itself rotates ina clockwise direction, does not in any wayinterfere with the air passing through the fan and serves to guide thisair in the same way as the solid guide would.

It is pointed out that no units are given for the above discussedrelationships since the particular size of the fan is a matter ofchoice. In other words, the radius of the inner cylinder 44 may be 1, or6", or 2', or any other desired dimension depending upon the conditionsto be met by the fan. It is only important that the several parts of thefan have the relationships indicated in FIG. 4 and described above, andeven here all of these relationships are approximate. Furthermore, theradius of curvature of the wall portion 48 should be equal to thedistance between the plane 47 and the center of the radius of curvatureof the end portion of wall 30 next to the outlet 38.

The structure of the present invention may take many different forms.Thus, FIGS. 7-9 are respectively side, end, and top plan views of a fanconstructed in accordance with the present invention and having itshousing 30a shaped so as to direct air after passing through the fan ina direction Which makes an angle of 90 with the air entering the fan.FIGS. 7-9 further show diagrammatically the motor 15 which drives theimpeller through the belt '1. Any suitable means may be provided toadjust the tension of the belt 51. As is indicated in dotted lines inFIG. 7, the walls of the casing 30 which are next to the impellerconform to the above requirements.

FIG. 10 shows an arrangement where the casing 30b is shaped so as todirect the air issuing from the fan at an angle of 45 with the airentering the fan. FIG. 11 shows an arrangement where the casing 30c isshaped to direct the air leaving the fan in a direction which makes anangle of 0 with the air entering the fan, and FIG. 12 shows anarrangement similar to that of FIGS. 7-9 in that the air is deflectedthrough 90 by the casing 30d after passing through the fan. However, itwill be noted that the air enters and leaves the casing 30d at an angleof 45 with respect to a horizontal plane.

As is shown in the dotted lines of FIGS. 10-12, the walls of the casings39b, 30c, and 30d, where they are located next to the impeller conformclosely to the requirements discussed above in connection with FIG. 4.

It has been found that with the fan of the invention, which may becalled a cross flow fan, produces far less noise at a given speed ofrotation than either a radial or axial flow conventional fan operatingat the same speed of rotation. Furthermore, it will be noted that thefan of the invention may have its impeller located directly within aduct, so that very little space is required for the fan of theinvention. The impeller may be made of any desired length, since thelength of the impeller in no way influences the operation of the fan ofthe invention. In order to vary the output of the fan of the invention,it is only necessary to change the speed of rotation of the impelleraccordingly. Furthermore, with the fan of the invention there are nooperating characteristics which change suddenly at two speeds ofoperation which are close to each other. in other words, when increasingor decreasing the speed of rotation of the fan of the invention there isno danger of passing through certain critical speeds as is the case withknown fans.

While the invention has been illustrated and described as embodied incross flow fans, it is not intended to be limited to the details shown,since various modifications and structural changes may be made withoutdeparting in any way from the spirit of the present invention.

Without further analysis, the foregoing Will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. A fan comprising, in combination, impeller means having apredetermined direction of rotation including a plurality of elongatedimpeller blades of substantially the same length uniformly distributedabout a cylindrical space and respectively having inner side edgeslocated along a first cylinder and outer side edges located along asecond cylinder coaxial with and greater than said first cylinder, saidblades being substantially parallel to the common axis of saidcylinders, and a casing supporting said impeller means for rotationabout said axis, said casing having an inlet communicating at any giveninstant with a first plurality of blades located on one side of saidaxis and with an outlet communicating'at any given instant with a secondplurality of blades located at an opposite side of said axis, and saidcasing including a first arcuate wall portion extending from said inletto said outlet in the predetermined direction of rotation of theimpeller and located closely adjacent to and conforming to the curvatureof said second cylinder, and a second arcuate wall portion opposite saidfirst wall portion also extending from said inlet to said outlet in adirection opposite to that of said predetermined direction of rotationof the impeller and spaced throughout its length from the curvature ofthe second cylinder by a distance substantially greater than thedistance between the first wall portion and the second cylinder, andhaving end portions respectively located adjacent said inlet and outletwith said end portion adjacent said inlet located nearer to said axisthan said end portion adjacent said outlet, so that said second wallportion forms with said second cylinder a gap which converges from saidoutlet toward said inlet in the predetermined direction of rotation ofsaid impeller, whereby a part of the fluid flowing from the inlet to theoutlet is reversed and fiows backward into said gap and then through theblades into the interior of the cylindrical space.

2.. In a fan as claimed in claim 1, each of said blades having, whenlocated adjacent said gap, a concave face directed toward said inlet.

3. In a fan as claimed in claim 1, each of said blades having, whenlocated adjacent said gap, a concave face directed toward said inlet anda convex face directed toward said outlet.

4. In a fan as claimed in claim 1, said inlet and outlet each having arectangular cross section, each extending about said axis through anangle of more than and the angle through which said inlet extends aboutsaid axis being greater than that through which said outlet extendsabout said axis.

5. In a fan as claimed in claim 1, the outer portion of each blademaking with a tangent to said second cylinder an angle of between 25 and45 6. In a fan as claimed in claim 1, said second cylinder having aradius approximately 1.25 times that of said first cylinder.

7. In a fan as claimed in claim 1, each blade itself forming a part of acylinder.

8. In a fan as claimed in claim 1, each blade itself forming a part of acylinder having an axis located be tween said first and second cylindersand adjacent the next blade.

9. In a fan as claimed in claim 1, said se'cond wall portion having aradius of curvature slightly less than the radius of said firstcylinder.

10. In a fan as claimed in claim 1, each blade itself forming part of acylinder having an axis located between said first and second cylindersand adjacent the next blade, said blades each making with a tangent tosaid second cylinder an angle of between 25 and 40, and said secondcylinder having a radius approximately 1. 25 times that of said firstcylinder, said inlet and outlet each having a rectangular cross section,each extending about said axis through an angle of more than 90, and theangle through which said inlet extends about said axis being greaterthan that through which said outlet extends about said axis, said secondwall portion having a radius of curvature slightly smaller than theradius of said first cylinder, and each of said blades having, when itis located adjacent said gap, a concave face directed toward said inletand a convex face directed toward said outlet.

11. In a fan as claimed in claim 1, said inlet and outlet making anangle of 45 with respect to each other.

12. In a fan as claimed in claim 1, said second arcuate 7 wall portionbeing cylindrical and having its axis eccentric to the axis of saidcylinders.

13. In a fan as claimed in claim 12, said arcuate wall portion axisbeing located downstreamward with respect to the axis of said cylinders.

14. In a fan as claimed in claim 13, the radius of curvature of saidarcuate portion being less than the distance from the said arcuateportion to the axis of said cylinders.

15. A fan comprising, in combination, impeller means having apredetermined direction of rotation including a plurality of elongatedimpeller blades of substantially the same length uniformly distributedabout a cylindrical space and respectively having inner side edgeslocated along a first cylinder and outer side edges located along asecond cylinder coaxial with and greater than said first cylinder, saidblades being substantially parallel to the common axis of saidcylinders, and a casing supporting said impeller means for rotationabout said axis, said casing having an inlet communicating at any giveninstant with a first plurality of blades located on one side of saidaxis and with an outlet communicating at any given instant with a secondplurality of blades located at an opposite side of said axis, and saidcasing including at first arcuate wall portion extending from said inletto said outlet in the predetermined direction of rotation of theimpeller and located adjacent to said second cylinder, and a secondarcuate wall portion opposite said first wall portion also extendingfrom said inlet to said outlet in a direction opposite to that of saidpredetermined direction of rota tion of the impeller and spacedthroughout its length from thecurvature of the second cylinder andhaving end portions respectively located adjacent said inlet and outletso. that said second wall portion forms with said second cylinder a gapwhich converges from said outlet towards said inlet in the predetermineddirection of rotation of said impeller whereby a part of the fluidflowing from said inlet to the outlet is reversed and flows backward]into said gap and then through the blades into the interior of thecylindricdl space.

16. A fan of the type comprising a hollow rotor having a.pluralityofelongated impeller blades, a casing surrounding said rotorand forming for said rotor an inlet and outlet, and rotation means forrotating said rotor; said casing inclzlding a firstwall portion adjacentto said rotor at said. inlet: and diverging therefrom to said outlet inthe direction of rotation of said rotor and a second wall portion.spaced from said rotorextending from said outlet to said inlet in thedirection of rotation of said rotor with the space between said secondwall portion and said rotor forming an unrestricted flow passage gaphaving at its opening adjacent said outlet a greater cross-sectionalarea taken in a radial plane to said rotor than the cross-sectional areaof its opening adjacent said inlet taken in a radial plane to said rotorand wherein said gap converges along its length extending from saidoutlet to said inlet; said rotor when rotated forming a fluid vortexwherein the core of the vortex extends partially into said gap and intosaid rotor and the center of the core of the vortex is positionedinwardly of the outer periphery of the rotating blades so that thevortex guides the flow of fluid from said inlet to said outlet.

17. A fan of the type comprising a hollow rotor having a plurality ofelongated impeller blades, a casing surrounding said rotor and formingfor said rotor an inlet and an outlet, and rotation means for rotatingsaid rotor; said casing including a first wall portion spaced fromsaidrotor extending from said inlet to said outlet in the direction ofrotation of said rotor, a second wall portion spaced from said rotorextending from said outlet to said inlet in the direction of rotation ofsaid rotor, and a vortex forming means comprising an unrestricted flowpassage gap formed by the spaced between said second wall portion andsaid rotor which converges from said outlet to said inlet whereby awhirling body of fluid is formed when said rotor is rotated and wherebya part of the fluid flowing from the inlet to the outlet flows into saidgap from the outlet and then through the path of the rotating bladesinto the interior of the rotor.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS

